Conventionally, as an apparatus that conveys articles by a conveying device such as a belt conveyor while inspecting whether the foreign object such as hair, dirt, small insect or the like is mixed in the article, or whether there is no defective part such as damage or breakage on the surface of the article, an apparatus using visible light, X-ray or magnetic field is known.
However, an inspection apparatus using X-ray or magnetic field also has an influence on the human body of an inspection worker, care is also taken in handling, and in many cases, the inspection apparatus performs automatic inspection by an imaging device such as a camera, which is very expensive.
Therefore, for food items such as vegetables and fruits, visible light is applied in a process of placing and conveying a food item on a conveying device such as a belt conveyor, and a worker has seen through the interior of the food item and has inspected whether a foreign object such as hair, dirt, small insect or the like is mixed in the food item.
In order to further improve the efficiency of such inspection work, an inspection apparatus is known in which a translucent thin-walled conveyor belt having light permeability is used, and white light is applied from the lower side of the conveyor belt with a fluorescent lamp so that the worker can see through the interior of a food item (see Patent Literature 1).
However, in the inspection apparatus described in Patent Literature 1, a fluorescent lamp is used. Therefore, light flickers, an inspection worker tends to be fatigued, work efficiency declines in a short time, and in the long term there is a possibility of impairing visual acuity, which also poses a health problem.
Also, since white light is used, depending on the color of the food item such as blue, red and yellow, it has been difficult to see through the interior of the food item by the light transmitted through the food item and the light transmitted through the conveyor belt.
Furthermore, because fluorescent light is used, the electric power consumption is inevitably large, so that the electricity fee is inevitably expensive. The irradiation device is large, so that the whole apparatus has to be large in size as well.
Therefore, the inventors of the present application developed an article inspection apparatus that can solve the above problem, makes a worker less tired to maintain work efficiency, is free from the risk of impairing visual acuity, has no problem in terms of health, can efficiently perform visual inspection, has low power consumption, and can make the entire apparatus small (see Patent Literature 2).